This was helpful to me: "From Celia Boertlein: http://www.census.gov/prod/cen2000/doc/sf2.pdf Appendix H "Characteristic Iterations" discusses the use of the population threshold in showing matrices for specific race groups, Indian and Alaska Native tribes, and Hispanic or Latino groups." And although initially confusing, this also helped: http://factfinder.census.gov/home/en/sf2.html Patty Becker's comments on the listserve were also helpful. I'm still feeling confused about the data privacy issue and why the rule applies to some, and not all of the SF releases. Seems a little inconsistent, but it may make more sense as the details unfold over time. ****************************************** I agree with your statement about the amount of info to digest when understanding the census. Can you explain what is meant by "Rule of 100"? Thanks! Kelli Peterson